Measuring device and measuring method for determining distance and/or position

ABSTRACT

A measuring device is provided with a signal generator and a signal receiver, which is located at a measurable distance from the signal generator. The signal generator is designed for the emission of at least two signal beams covering in given relationship to each other an area and the signal receiver is designed for the time-resolved reception of the signal beams in such a manner that the generator-receiver distance can be determined from the time signature of the signal beam reception.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional application of application Ser.No. 10/343,538, titled “MEASURING DEVICE AND MEASURING METHOD FORDETERMINING DISTANCE AND/OR POSITION,” filed on Jan. 31, 2003, now U.S.Pat. No. ______; which claims priority to PCT patent application No.PCT/EP01/08841, filed on Mar. 7, 2001; which claims priority to Germanpatent application No. 100 59 240.6, filed on Nov. 29, 2000 and Germanpatent application No. 100 37 853.6, filed on Aug. 1, 2000.

BACKGROUND

(1) Field of the Invention

The present invention relates to the characterizing clauses of theindependent claims. With these the invention generally deals withdetermining distances and/or positions.

(2) Description of Related Art

It is frequently necessary to be able to measure comparatively shortdistances in the range of several centimeters up to several hundredmeters fast and very precise. Applications for this are for examplemeasuring existing real estates, the measurement of properties, duringthe construction of houses, as well as measuring distances of mobilemachinery, for example transport systems in industrial halls, whosedistance from walls or such must be determined, in order to stop themovement if necessary before a collision occurs.

Beyond that it is often not only necessary to determine the distance fora point of reference but also to determine a relative position to thispoint of reference depending upon application in two or threedimensions, i.e. typically the position on an area or in addition alsothe height.

Now different methods are suggested, in order to deal with thesemeasuring tasks.

Thus for example the U.S. Pat. No. 5,949,530 suggests a method, whichemits a pulsed laser beam and determines the distance to a distantobject from the running time of the backscattered pulse. Systems of thistype are already used in industrial applications, they are howeverexpensive, as the running times of the light pulses are short and agating electronic operating at high frequency operating is required,which must respond accordingly quickly.

Further arrangements are well-known, in which signals are modulated onsignal beams and a value related to the modulation, e.g. the phase, isused for the determination of the distance to the signal generator.

Apart from the described timing of the interval between transmission andecho-return and the phase measurement with suitable modulated laserlight further methods are well-known like the active triangulation, withwhich e.g. backscattered laser light is detected with aposition-sensitive detector (PSD), in order to conclude the distance tothe object points from the position of a light spot imaged on thisdetector.

Further arrangements are well-known with which a light emitter isaligned accurately to the vertical lie, in order to then emit a lightbeam along a horizontal line or a system of coordinates as reference.Hereby measurements can be facilitated, however they cannot be takeneasily.

SUMMARY

The task of the present invention is to make the latest available forthe commercial application.

The solution of this task according to the invention is claimed inindependent form, preferable embodiments can be found in the sub claims.

Thus the invention suggests first that in a measuring device with asignal generator and a signal receiver, which is located at a measurabledistance from said signal generator, it is intended that the signalgenerator is designed for the emission of at least two signal beamscovering in given relationship to each other an area and the signalreceivers is designed for the time-resolved reception of signal beams insuch a manner that the generator-receiver distance can be determinedfrom the time signature of the signal beam reception.

A first substantial aspect uses thereby the fact that a receptionsignature is received at the signal receiver by the given relationshipof two separate signal beams to each other, which are moved in a givenway over an area. The distance to the signal generator can be concludedfrom said reception signature.

The measurement principle implemented thereby can be understood best,without limiting the invention to this special case, for two parallel toeach other emitted laser beams, which rotate together symmetrical aroundan axis, whereby the rotation axis is to be normal to the plane definedby the laser beams.

Due to the symmetrical rotation a laser beam requires at each distanceto the rotation axis always the same time in order to rotate oncecompletely. The length of the peripheral circle however, which the laserscans during a complete rotation, increases in a plausible way with thedistance to the rotation axis.

Now with parallel emission of the laser beams their distance is equal ineach distance to the rotation axis. However, this distance is scannedfaster at a larger distance to the axis, as the laser distance far awayfrom the axis constitutes a smaller fraction of the circumference. Thetime, which the second laser requires, in order to reach the position,at which the first laser was detected before, is thereby reduced if thedistance to the axis increases.

This measurement principle however is limited neither exclusively tolaser light, nor to only two, nor to accurately parallel aligned beams.Measurements can be conducted also with emitted beams tilted to eachother, skew beams or intersecting beams; it is also possible to intend anon-symmetrical rotation, for example in order to scan non-interestingareas faster or to be able to detect with a fixed installation of thesignal generator, e.g. in an industrial hall, certain areas withincreased resolution.

It is possible to use a set of different beams e.g. ultrasonic beams. Itis however preferred, if light beams are emitted as signal beams, asthis especially simplifies the control and adjustment of the device. Theuse of laser light beams is particularly preferable, since laser lightsources are available, are inexpensive and emit with only lowdivergence.

The signal beams can be made to scan an area in different ways. It isparticularly preferable, if they rotate around an axis. For this thesources of light can be arranged on a turntable or they can radiate on aturning optics. In such a case the signal beams will not intersect atthe rotation axis; the analysis of the signals is simplified, if atleast two of the signal beams are emitted generally parallel to eachother. However it is possible without problems to correct to other beamgeometries.

In a particularly preferred variation more than two signal beams areemitted. The signal beams can be emitted as general signal beam fans,whereby at least the plane created by a single fan exhibits at least onecomponent parallel to the rotation axis and is situated preferablygenerally parallel to said plane. This permits the use of detectors inthe signal receiver, which do not have to be arranged at a certainheight, in order to receive a signal, even if they are designedpunctiformly. Although a fan-like emission of other beams is alsopossible, for purely linguistic reasons in the following it is onlyreferred to the light fan.

Preferably a third light fan can be intended, which runs diagonallybetween two fans that surrounding it and which are generally rotationalparallel to their axes. The time, which generally passes between thepass of the two generally rotational parallel to their axes light fans,depends here only on the distance of the measurement location to therotation axis. Dependent on the height, in which the signals of thethree fans are received, varies both the time, which passes between thepass of the first, generally rotational parallel to their axes and thediagonal light fan, as well as the time, which passes between the passof the diagonal light fan and the second, generally rotational parallelto their axes light fan; if the first time increases, the second timedecreases accordingly, and reversed. Thus the height can be concludedfrom the time analysis.

It is particularly preferable, if the measuring device exhibits a meansfor the determination of a signal beam zero-angle passage.

This permits the reference to a zero-angle reference axis, whichprepares a set of polar coordinates at each measuring point by using thedistance to the rotation axis.

The synchronization to the zero passage can take place by modulation ofthe signal beams (e.g. laser beams) for instance with time information,by means of reference to an external time standard like a DCF-timesignal or network humming and/or a reference to a common internal and/orexternal time or cycle reference.

A zero-angle reference can be generated also by a single and/or multiplesynchronization of a receiver clock to the rotation speed of the laserunit and a following, continuous timing.

Furthermore a in particular wireless data communications device can beintended for the interchange of information between the units, inparticular the time information and/or the zero-angle passageinformation.

It is preferable, if the measuring device comprises further a means, inorder to determine Cartesian coordinates (x, y) from the distance to thesignal generator (r) and the reference to the signal beam zero-anglepassage (phi). The conversion can occur in the signal receiver, in orderto indicate directly there a given xy and respectively z-coordinate.

If the time signal evaluation occurs at least partially in the signalreceiver, it is preferable, if a multiplicity of coordinates can bestored in said signal receiver and/or can be transferred in particularto a central processing unit and/or a data processing unit.

It is in particular preferable for the signal receiver with light beamsas signal beams, if it exhibits at least one photo-sensitive component,which receives light from a light conductor, whereby its surface can bedesigned for the coupling of light hitting the lateral surface inparticular by dispersion.

It is particularly preferable, if a photo sensor is intended on bothends of the light conductor; then one receives alternatively aredundancy and increased failure security and/or the possibility toconclude the point of impact of a light beam interspersed into the lightconductor from a signal strength comparison at the first and secondphoto sensor. This can be used for height determination for example whenassembling mobile robots and/or for leveling work on construction sites,assuming that the height of the receivers above ground is known.

In an alternative way it is possible, to use a signal receiver withseveral integrated signal beam detectors located in a fixed distance toeach other in place of two or several moving signal beams, which areemitted to each other in a given spatial relationship. A distance to onepoint of reference can now be also concluded from the time course of thesignals created on the different signal beam detectors by that at leastone signal beam. The idea that a given angular velocity leads to scantimes varying with the radius dependent on the distance to the rotationaxis is used also here. It is here preferable to use again rod-shapedlight receivers, e.g. light detectors at light conductors, into whichlight can be coupled by interference. Preferably at least three of suchlight conductors are used at the same time. This makes it possible todetect and compensate for a diagonal tilt of the signal receiver. Adiagonal tilt by rotating against the tangent of the scanned circle canbe assumed thereby in particular if with equidistantly arranged signalbeam detectors the reception time differences deviate from the first tothe second signal beam detector and from the second to the third signalbeam detector significantly from each other. A diagonal tilt against therotation axis however can be detected, if the individual signal beamdetectors are height sensitive, e.g. through position-sensitivedetectors (PSDs) and/or light conductors scanned for intensity on bothsides, into which light can be coupled by interference. It is alsofavorable when using several signal beams at the same time to designateseveral, e.g. two, signal receivers located at a measurable distancefrom each other; with these preferably the three-dimensional orientationof an object, at which they are arranged, can being determined.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described following only in examples using thedrawings. Shown is/are:

FIG. 1 a draft for the representation of a measuring device according tothe invention;

FIG. 2 a a first principle draft for the representation of a gatingelectronic of a measuring device according to the invention;

FIG. 2 b a second principle draft for the representation with analternative gating electronic of a measuring device according to theinvention;

FIGS. 3 a, b signals at the two diodes of the signal receiver;

FIG. 4 a detail of a signal receiver;

FIG. 5 a principle draft of a further measuring device according to theinvention;

FIG. 6 details of signal receivers;

FIG. 7 an alternative beam geometry;

FIG. 8 different variations for the design of the signal generatoraccording to the invention;

FIG. 9 examples of applications;

FIG. 10 a further variation.

DETAILED DESCRIPTION

According to FIG. 1 a measuring device for local position determination,generally denoted with 1, comprises a signal generator 2 and severalsignal receivers 3 a, 3 b located at a measurable distance from saidsignal generator.

The signal generator 2 comprises a platform 2 a, on which two laserlight sources 2 b, 2 c are located for the emission of generallyparallel signal beams. The lasers 2 b, 2 c can be rotated around arotation axis 2 d together with the platform 2 a by a drive unit 2 ewith controlled, constant speed; said rotation axis runs generallyvertically and is normal to the generally parallel laser beams.

A radio signal generator, which beams a signal referred to the point intime t₀ of a zero-angle passage is not shown.

The first signal receiver 3 a is a stationary signal receiver, while thesecond shown signal receiver 3 b is a handheld signal receiver.Generally it is possible to use practically as many receivers at thesame time as desired. The two signal receivers 3 a, 3 b have360°-characteristics, which means they can receive light from alldirections. They comprise a light conductor 4; its surface is providedwith a dispersing coating and each end of the light conductor exhibits aphotodiode 5 a, 5 b as the photo-sensitive component. Signal receiver 3a or 3 b comprises also a radio receiver 6 e (see FIG. 2 a), which isdesigned for the reception of the signal emitted from the signalgenerator referred to the zero-angle passage.

Referring now to FIG. 2 a, signal lines lead from the photodiodes 5 a, 5b to a signal processing circuit 6 including component 6 a, which isdesigned to first amplify the signals and condition them in such a waythat the status, in which a signal beam is coupled into the lightconductor, can be identified and be detected regarding its temporalposition t₁, relative to the time of the zero-angle passage t₀. Thesignal processing circuit 6 is designed further to determine the timedifference Δt (FIG. 3) from sequential photodiode pulses and to derivefrom this further information using measuring device 6 b. For this,converter 6 c is present, which is designed to determine an anglecoordinate φ relative to the point of zero-angle transit time t₀ fromthe temporal position of t₁ of the corresponding photodiode pulses andto output it to output 6 d, and which is further designed to determinefrom the time difference At a distance to the signal generator. Theresults from converter 6 c are given to output 6 d, with which theresult can be displayed locally on a display.

The arrangement of FIG. 1 is used as follows:

First the drive unit 2 e is excited, until the desired constant speedaround the rotation axis 2 d is controlled. Then the signal generators 2are excited. This creates pulses in the photodiodes 5 of the signalreceiver 3 b, if these are hit by the signal beams. These signalsbelonging to the pulses become amplified and conditioned.

Now the time signature of the signal generator reception is determinedwith the signal receiver 3 b. First the temporal distance of thedetected signals is determined and from this the distance between signalreceiver and rotation axis is determined.

It is taken advantage of the fact that a laser beam through symmetricalrotation requires in each distance to the rotation axis always the sametime, in order to rotate once completely, at the same time however thelength of the periphery circle, which the laser scans with a completerotation, increases with the distance of the rotation axis. Since withparallel emission of the laser beams their distance is the same in eachdistance to the rotation axis, this distance however is covered fasterat a larger distance to the axis, since the laser distance far away fromthe axis constitutes a smaller fraction of the periphery. The time,which the second laser requires, in order to reach the position, atwhich the first laser was detected before, is thereby reduced if thedistance to the axis increases. A value referred to the reciprocal valueresults therefore in a value characterizing the distance to the rotationaxis.

Therefore first a size reciprocal to the temporal distance of thedetected signals is calculated and then the distance to the rotationaxis is determined by referring to a value that describes thegeometrical arrangement of the emitted signal beams and the fixedrotational frequency.

The time difference Δt is thereby converted in converter 6 c to adistance to the signal generator and is given to output 6 d, whichdisplays the result locally on a display.

The angle coordinate φ is then determined relative to the time ofzero-angle passage t₀ from the temporal position t₁ of the respectivephotodiode pulses and is output at output 6 d.

It is to be mentioned that light conductors 4 at signal receiver 3 canbe designed in different ways for the light coupling. This is shown inFIGS. 4 a-4 f.

In FIG. 4 a a light conductor is shown, its surface is provided with adispersing coating and a photodiode is intended at its lower end.

Alternatively FIG. 4 b shows the use of a dispersing core 20 on theinside of light conductor 4 and/or wave guide. The path of the beams issketched. Light conductor 4 shown in FIG. 4 c uses dispersing particlesfor the coupling of the laser light. With light conductor 4 shown inFIG. 4 d, a reflection layer located at one end serves the purpose ofsignal amplification in particular with longer light conductors. FIG. 4e shows on the contrary to FIG. 4 a a partially surface coveringdispersing layer 21. Here the light is coupled preferably through lightconductor 4 from the side opposite to dispersing layer 21.

FIG. 4 f shows a particularly preferred variation of light conductor 4,which makes it possible to determine the position of the point of impactof the laser beams by the use of two photodiodes 5 a and 5 b at bothends of light conductor 4. Light conductor 4 according to FIG. 4 f isused thereby for the stationary signal receiver 3 a (FIG. 1), as therebyin connection with the measurable deflection of an integrated telescopemeasuring pole 3 a′, a height measurement (leveling) is possible.

The design example of FIG. 5 shows an enhancement of the inventionpreviously described for the determination of three-dimensionalcoordinates. First of all deviating from the previous design example nolight beams are emitted, but light fans 7 a, 7 b, 7 c are emitted fromlight fan emitters 7 a′, 7 b′, and 7 c′, respectively. The two edge fans7 a, 7 c are thereby generally parallel to each other and to therotation axis 8; middle light fan 7 b is tilted against the two lightfans 7 a, 7 c. The platform is again provided with a zero-anglereference, which outputs an additional radio signal to the signalreceiver 3 c each time an arbitrarily defined zero-angle is scanned. Thesignal receiver 3 c exhibits an at least essentially punctiform lightcoupling area 3 e (FIG. 6).

With this arrangement three-dimensional coordinate determinations can beexecuted as follows: First, as previously described, the time signatureof the measuring signal reception is determined and the distance to therotation axis is concluded from the distance of the passage of bothouter light fans 7 a and 7 c. As previously described, the angleposition of signal receiver 3 c relative to the arbitrary zero-angle isdetermined by reference to the determination of scanning the zero-anglepassage, in accordance with radio signal transfer. In addition, it isnow determined, in which ratio the period between the passage of twoouter light fans 7 a, 7 c is divided by middle, diagonally tilted lightfan 7 b. It can be clearly understood that this relation isrepresentative for the height (with given radius), which is calculatedas coordinate z. This way a set of coordinates r, phi, z is determined.These cylindrical coordinates are then converted into Cartesiancoordinates.

While according to the example in FIG. 1 the laser beams were emittedgenerally normal to the rotation axis, this is not mandatory. Rather itis also possible to choose a conical emission in place of a planeemission, as shown by signal generator 2′ in FIG. 7.

While it was previously described that the lasers themselves are rotatedas sources of signal beams, this is not mandatory. Referring now to FIG.8 a, it is also possible to direct the laser beam toward a rotatingmirror or similar device, such as rotating mirror 14. In the case ofrotation of a polygon the beams move somewhat apart, what can becompensated during the analysis, however very high speeds can beachieved. Furthermore it is possible to intend only scanning of acertain area, for example by a periodic to-and-fro swiveling instead ofa complete rotation of lasers 2 b and 2 c and/or rotating visualcomponents.

As shown in FIG. 8 b, it is also possible to divide a single laser beam,i.e., from laser 2 b, into several signal beams by a beam splitterarrangement, such as beam splitter 14 located on platform 2 a atrotation axis 2 d. Similarly, as shown in FIG. 8 c, it is possible todivide a single light fan from light fan emitter 7 a′ into several lightfans 7 a, 7 b, 7 c by beam splitter 15 located on platform 2 a atrotation axis 2 d.

The measuring device can be used for example in one of its arrangementswith self-contained mobile robots, with transport systems withoutdriver, with applications of robotics or for machinery control, or withconstructional surveying technology and replaces and/or completes thereconventional electronic measure tapes, like laser distance meters orultrasonic distance meters, stationary or rotary leveling lasers, inparticular also leveling lasers with adjustable inclination (e.g.rotation laser with two inclination axes, canal construction lasers),visual leveling instruments, in particular digital leveling instruments,optical and/or electronic theodolites and total stations. Furthermore itis possible to use the measuring device according to the invention formeasuring and staking out of building ground plans for new buildings(preparation of batter boards), for surveying work of constructionsites, for example for checking the construction against the plan(accuracy to size) as well as for area calculation, for surveying ofexisting buildings for subsequent area calculations or for examinationof individual measurements of a building, for manual transferring ofplan data (in particular CAD data) to a background (floor, wall,ceiling) for construction industry, industry, landscaping, building offairs, etc., measuring of markings during sports events, measuring ofachieved distances during sports events for example in the disciplinesjavelin-throw, hammer-throw, shot-put, broad jump, etc.,surveying/design of vehicles (ships, airplanes, etc.), use as trackingsystems for virtual reality systems, in particular for so-called virtualstudios, for canal construction, for example for laying pipe 25, asshown in FIG. 9 a.

Furthermore it is possible to support the generating of environmentalmodels for mobile applications of robotics. A further application is todetermine the position of mobile service robots. In particular for alltypes of the surface covering ground work, for example buildingcleaning, lawn maintenance, installation of floor tile, mine search(humanitarian demining), etc.

A particularly preferred variation intends that a mobile system isprovided with a measuring device on the one hand and with a markertransmitter on the other hand, that triggers certain positions and setsmarkings when reaching said positions for example in order to transferCAD floor plans 1:1. Referring now to FIG. 9 b, the actual position of amobile robot 10 is determined repeatedly; then with consideration of thesame actual position desired positions are approached—and markings 11set on these as required.

It is to be pointed out that through the use of several signalgenerators both the area coverage as well as the measuring accuracy canbe increased. Further it is explained that an overall system can consistof one or more signal generators and of one or more receivers (positiondetectors), whereby almost as many as desired receivers can be used atthe same time and operated independently from each other, as long as thedirect line of visual connection between the scanner unit and a receiveris preserved for a sufficient number of beams, usually two.Independently of the individual application thereby a multiplicity ofreceivers can be operated at the same time, so that manual measuring ofseveral coworkers or the controlling of several machines at the sametime becomes possible, which is favorable in industrial halls, in orderto route transport systems without driver. From this result asubstantial time gain and a substantial cost saving, because only onestation permanently installed is required at the same time and contraryto the use of theodolites only the relatively inexpensive receivers haveto be present manifold.

The models of the possible receivers extend from simple x/y-displayswith one-button operation up to comfortable measuring poles withintegrated small computers, so-called Personal Digital Assistant—PDAs,which offer software interfaces to common CAD-programs.

Because the measuring accuracy at larger distances is determinedparticularly by the temporal resolution of the measurement of thedistance between the pulses, the accuracy can be increased by multiplemeasurements and following averaging. This is also favorable forcorrecting measured values with air turbulences etc., in particular formeasurements in a large distance to the signal generator.

The zero-angle passage can be generated by the receiver different thanpreviously described also by a one-time synchronization of a receiverclock to the rotation speed of the laser unit and a following,continuous timing.

Particular wireless data communications equipment for the exchange ofinformation between the units can be intended.

LCD indicators or the like can be intended in the receivers, in order toindicate the position directly.

It is to be pointed out that the light conductors, designated at thesignal receivers, into which light is laterally coupled by dispersionand/or with which on both ends of the light conductor an photo-sensitivecomponent is intended, offer also benefits independently of the use ofthe arrangement according to the invention. This arrangement can be usedin particular for the measuring of altitudes, also with conventionalrotation lasers.

A further variation of the measuring device is shown in FIG. 2 b asmeasuring device 6 b′. In this variation, the signal received from thephotodiode is quantized time-discrete and value-discrete afteramplification through analog/digital converter 6 f′ for the betterdetermination of the impact of the laser beam on the signal receiver andthe gravity center of the signal received with the transmission beampassage is algorithmically determined at the received digital datastream, in order to determine the point of passing through of the beamto this point of passing through of the gravity center. By determiningthe point of passing through of the gravity center as the point ofpassing through of the beam time, the temporal precision of theregulation can be increased; in particular the precision is better thanit is possible by the given scanning rate.

Furthermore the shown variation is arranged to conduct at the digitaldata stream a digital signal conditioning e.g. in form of an offsetadjustment and/or by using an evaluation function (weighting function),e.g. a peripheral location attenuation, in order to achieve a furtherimproved detection of the temporal beam passage. It is to be pointed outthat it is possible to conduct a laser beam modulation at the signalgenerator for measurements with low signal levels. If desired, therequired demodulation in the receiver can take place in a digitaldemodulation unit, assuming the presence of sufficiently high scanningrates during quantization.

A variation of the invention with only one beam is described withreference to FIG. 10.

The measuring device shown in FIG. 10 a permits thereby atwo-dimensional positioning with only one signal beam. The directedsignal beam emitted by the signal generator normal to its axis ofrotation scans in the course of a rotation a signal receiver 3 d, whichis equipped with three rod sensors 20 according to FIG. 4 f. Rod sensors20 are parallel to the rotation axis. The signal beam is here collimatedand not widened fan-like.

The angles β, α1 and α2 come as crude data results from the timesignature of the signal reception, whereby α1 and α2 are determined bymeasurement of the time intervals between the pulses of the signal beamdetectors and β is determined by determining the time difference betweenthe measuring pulse at one detector 20 (preferably the middle detector)and the zero-angle reference signal.

A non-parallel position of the signal receiver to the rotation axis canbe compensated in accordance with FIG. 10 b. FIG. 10 b shows the topview onto the active side of the signal beam receiver 3 d. Thereby thethree signal beam detector 20 are arranged parallel and with thedistances d₁ and d₂ in one plane. The beam crosses signal beam receiver3 d on a path that is tilted with the angle δ, so that the point ofimpact divides each light conductor in different ratio. In order to beable to determine now the points of impact of the signal beam in thelocal coordinate system (x_(s), y_(s)) of signal receiver 3 d, thisone-dimensional height information of rod sensors 20 must be analyzed.This can take place by means of analysis of the signal strengths on thetwo photodiodes located at the ends of each light conductor 20. As thedistances d₁, d₂ are known, the base distances b₁, b₂ required for thedetermination of the distance r can now be calculated. This way thedistance r can be calculated from α₁ and α₂ and the base distances b₁and b₂.

Instead of the light conductor configuration are also different sensors,e.g. PSDs applicable.

A measuring device in accordance with FIG. 10 allows generally besidesthe determination of the distance r and the angle beta also a heightmeasurement regarding the plane in the coverage area of the lightconductor/PSDs, said plane created by the rotating signal beams.

Furthermore it is possible to conduct also the determination of thepolar coordinates angle beta without taking reference on the transfer ofan angle reference; the accurate position of the signal receiverrelative to a signal generator can be determined nevertheless, in atleast two coordinates (r, phi). For this a signal generator with almostconstant rotational speed is used, which can also be for example aninexpensive, known rotating leveling laser. With the signal generatorshown in FIG. 10 first a measurement is taken at a first position. Thenthe signal generator is offset by a well-known distance and a newmeasurement is taken with the signal receiver in this position. Thewell-known distance must only be known regarding its length, what can bedetected easily from the time signature at the signal receiver, which isoffset to the previous or desired second position of the signalgenerator. The determination of the polar coordinates takes then placethrough well-known trilateration. Before offsetting the signal generatormeasurements can be conducted in several positions by storage of thesingle measured values, whereby for these the measurements are to berepeated after offsetting the signal generator in order to be able todetermine the positions of the measuring points altogether.

In an alternative way it is possible to use two signal generators rightfrom the beginning. This is possible in particular if both signalgenerators can be differentiated at the receiver. This can take placevia different rotational frequencies, coding of the emitted signals,selection of a suitable emission spectrum and similar. The distance ofboth signal generators, which are positioned randomly to each other, isthen determined by conducting a measurement with the signal receiver forexample on the connection line between the signal generators.

In a particularly preferred variation, inertial sensors are intended inthe signal receiver, with which a movement of the signal receiver can bedetected.

Background here is in particular that, in particular for measurementsoutdoors over long distances, measurement inaccuracies caused byrefraction can occur from measurement to measurement due to the airturbulences. If it is detected whether and/or to what extent the signalreceiver moved between two measurements, is possible it to make anaveraging which increases the accuracy of the measurement. This canoccur also with consideration of measured values taken under movement.If measured values are stored, which were detected at the measurementlocation during the movement, then the measuring accuracy can beincreased by consideration of values, which were detected during themovement around that or to the measuring point under analysis of thetrajectories determined with the inertial sensors or such. In place ofthe inertial sensors other motion sensors for the detection ofmovements, adjustment and/or acceleration can be intended. It is clearlyunderstood that when designating such sensors also the movement of thesignal receiver during a measurement can be compensated.

All documents cited in the Background of the Invention and in theDetailed Description of the Invention are, in relevant part,incorporated herein by reference; the citation of any document is not tobe construed as an admission that it is prior art with respect to thepresent invention.

The foregoing description of a preferred embodiment of the invention hasbeen presented for purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formdisclosed. Any examples described or illustrated herein are intended asnon-limiting examples, and many modifications or variations of theexamples, or of the preferred embodiment(s), are possible in light ofthe above teachings, without departing from the spirit and scope of thepresent invention. The embodiment(s) was chosen and described in orderto illustrate the principles of the invention and its practicalapplication to thereby enable one of ordinary skill in the art toutilize the invention in various embodiments and with variousmodifications as are suited to particular uses contemplated. It isintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

1. A signal processing circuit for a light receiver having at least onephoto-sensitive component for repeatedly receiving a moving light beam,said signal processing circuit being adapted for receiving a signalderived from said photo-sensitive component and for determining thereception of said light beam on said photo-sensitive component, whereinsaid signal processing circuit comprises an analog/digital converter forquantizing a signal derived from said photo-sensitive component in atime and value discrete manner and for providing a stream of digitaldata related thereto, and said signal processing circuit being adaptedto determine details of the beam transit over said photo-sensitivecomponent from the quantized signal.
 2. The signal processing circuit ofclaim 1, wherein the details of the beam transit comprise the transittime determined from the temporal center of gravity of the beam passageand/or the exact position of impact of the beam onto aposition-sensitive photo-sensitive device in response to the data streamof time discretely and value discretely digitized signals.
 3. Ameasuring system, comprising: a signal receiver including a signalprocessing circuit, said signal processing circuit having at least onephoto-sensitive component for repeatedly receiving a moving light beam,said signal processing circuit being adapted for receiving a signalderived from said photo-sensitive component and for determining thereception of said light beam on said photo-sensitive component, whereinsaid signal processing circuit comprises an analog/digital converter forquantizing a signal derived from said photo-sensitive component in atime and value discrete manner and for providing a stream of digitaldata related thereto, and said signal processing circuit being adaptedto determine details of the beam transit over said photo-sensitivecomponent from the quantized signal; and a signal generator for emittingat least two signal beams which scan a surface in relation to each otherin a defined manner, said signal receiver being adapted to time resolvesignal beams reception in order to enable the distance between atransmitter and a receiver to be determined from the time signature ofsignal beams.
 4. The measuring system according to claim 3, whereinlaser light beams are emitted as signal beams.
 5. The measuring systemaccording to claim 3, wherein the signal beams rotate around a commonaxis.
 6. The measuring system according to claim 5, wherein the signalbeams do not intersect at the rotation axis.
 7. The measuring systemaccording to claim 3, wherein the beam axes of the signal beams arestationary to each other in a fixed manner and have a constant anglerelation.
 8. The measuring system according to claim 3, wherein at leasttwo of the signal beams are generally parallel to each other.
 9. Themeasuring system according to claim 3, wherein at least three signalbeams are provided.
 10. The measuring system according to claim 3,wherein the signal generator is designed to emit a signal beam fan. 11.The measuring system according to claim 10, wherein at least two of thesignal beam fans are arranged at least generally parallel to each other.12. The measuring system according to claim 11, wherein a third signalbeam fan is provided in such a manner that it is aligned diagonally tothe two signal beams, said two signal beams being located at ameasurable distance from each other, preferably generally parallel toeach other, and wherein said third signal beam then is arranged in aplane which is tilted towards the rotation axes however is not normal tothe rotation axes.
 13. The measuring system according to claim 3,comprising a means to determine a signal beam zero-angle passage. 14.The measuring system according to claim 13, wherein the means todetermine a signal beam zero-angle passage comprises a time based signalreceiver and/or a zero-angle passage signal receiver, in particularadapted for the wireless reception of an identification signal for thezero-angle passage.
 15. The measuring system according to claim 13,wherein the means to determine a signal beam zero-angle passagecomprises a means for beam modulation/demodulation.
 16. The measuringsystem according to claim 3, wherein a means for storing of amultiplicity of successive recorded coordinates is provided.